diff --git a/sql/funcs.go b/sql/funcs.go
new file mode 100644
index 00000000..369d2acb
--- /dev/null
+++ b/sql/funcs.go
@@ -0,0 +1,173 @@
+// Copyright © 2016 Abcum Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sql
+
+var funcs = map[string]map[int]bool{
+
+	"abs": {
+		1: true,
+	},
+
+	"avg": {
+		1: true,
+	},
+
+	"ceil": {
+		1: true,
+	},
+
+	"count": {
+		1: true,
+	},
+
+	"date": {
+		0: true,
+		1: true,
+	},
+
+	"day": {
+		0: true,
+		1: true,
+	},
+
+	"derivative": {
+		1: true,
+	},
+
+	"difference": {
+		1: true,
+		2: true,
+		3: true,
+		4: true,
+		5: true,
+		6: true,
+		7: true,
+		8: true,
+		9: true,
+	},
+
+	"distinct": {
+		1: true,
+	},
+
+	"floor": {
+		1: true,
+	},
+
+	"hour": {
+		0: true,
+		1: true,
+	},
+
+	"intersect": {
+		1: true,
+		2: true,
+		3: true,
+		4: true,
+		5: true,
+		6: true,
+		7: true,
+		8: true,
+		9: true,
+	},
+
+	"max": {
+		1: true,
+	},
+
+	"mean": {
+		1: true,
+	},
+
+	"median": {
+		1: true,
+	},
+
+	"min": {
+		1: true,
+	},
+
+	"mins": {
+		0: true,
+		1: true,
+	},
+
+	"mode": {
+		1: true,
+	},
+
+	"month": {
+		0: true,
+		1: true,
+	},
+
+	"now": {
+		0: true,
+	},
+
+	"percentile": {
+		1: true,
+	},
+
+	"round": {
+		1: true,
+	},
+
+	"stddev": {
+		1: true,
+	},
+
+	"sum": {
+		1: true,
+	},
+
+	"table": {
+		1: true,
+	},
+
+	"thing": {
+		2: true,
+	},
+
+	"union": {
+		1: true,
+		2: true,
+		3: true,
+		4: true,
+		5: true,
+		6: true,
+		7: true,
+		8: true,
+		9: true,
+	},
+
+	"unixtime": {
+		0: true,
+		1: true,
+	},
+
+	"uuid": {
+		0: true,
+	},
+
+	"variance": {
+		1: true,
+	},
+
+	"year": {
+		0: true,
+		1: true,
+	},
+}
diff --git a/sql/funcs/abs.go b/sql/funcs/abs.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/abs.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/avg.go b/sql/funcs/avg.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/avg.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/ceil.go b/sql/funcs/ceil.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/ceil.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/count.go b/sql/funcs/count.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/count.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/date.go b/sql/funcs/date.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/date.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/day.go b/sql/funcs/day.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/day.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/difference.go b/sql/funcs/difference.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/difference.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/distinct.go b/sql/funcs/distinct.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/distinct.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/floor.go b/sql/funcs/floor.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/floor.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/hour.go b/sql/funcs/hour.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/hour.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/intersect.go b/sql/funcs/intersect.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/intersect.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/max.go b/sql/funcs/max.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/max.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/mean.go b/sql/funcs/mean.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/mean.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/median.go b/sql/funcs/median.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/median.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/min.go b/sql/funcs/min.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/min.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/mins.go b/sql/funcs/mins.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/mins.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/mode.go b/sql/funcs/mode.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/mode.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/month.go b/sql/funcs/month.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/month.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/percentile.go b/sql/funcs/percentile.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/percentile.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/round.go b/sql/funcs/round.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/round.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/stddev.go b/sql/funcs/stddev.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/stddev.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/sum.go b/sql/funcs/sum.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/sum.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/union.go b/sql/funcs/union.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/union.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/unixtime.go b/sql/funcs/unixtime.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/unixtime.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/uuid.go b/sql/funcs/uuid.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/uuid.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/variance.go b/sql/funcs/variance.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/variance.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs
diff --git a/sql/funcs/year.go b/sql/funcs/year.go
deleted file mode 100644
index c5523f80..00000000
--- a/sql/funcs/year.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright © 2016 Abcum Ltd
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package funcs